Many different resinous materials are subject to invasion by a wide variety of microorganisms in that the microorganisms are free to multiply with little or no inhibition while in contact with the resinous material. These organisms, such as fungi and bacteria, damage the resinous materials both by metabolizing any plasticizer and lubricant that may be present in the materials, thereby rendering them stiff, and also by esthetically discoloring and defacing the resinous materials themselves. To prevent the proliferation of all types of microorganisms on such materials, chemical compounds are often added. It is desirable that these additives be effective at concentrations sufficiently low to have no deleterious effects on the resinous material, and at the same time be effective against as wide a spectrum of microorganisms as possible.
The nature of the resinous material does not matter. Many resins in bulk, film or other form are by themselves normally defenseless against bacterial growth on their surfaces. Such resinous materials include, for example, the polyvinyl resins such as polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, the various acrylic resins and methacrylic resins, such as polymethacrylate; polyolefins such as polyethylene, polypropylene, and polyisobutylene; polyurethanes; elastomers such as styrene-butadiene copolymers; butadiene-acrylonitrile copolymers; celluloses such as methyl cellulose, ethyl cellulose; and still others.
Further, it is not necessary for a resinous material to be in solid form to be subject to attack by fungi and bacteria. Liquid paint, for instance, is so subject and water-based paints such as the known water-based latex paints are especially subject to attack by Gram-negative bacteria. Even though such paints are fairly sealed in containers, Gram-negative bacteria can reach and cause the paint to spoil and become smelly and stringy in composition. When this happens, the paint cannot be applied to a substrate.
Among the bacteria which propagate on organic resinous material, for example of the type mentioned, are Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Escherichia coli is a common contaminant of water and sewage. It is a ubiquitous organism, found especially frequently and in high concentration in the digestive track of humans. It is commonly used as an index of pollution, for where it is located in large numbers it indicates pollution by human excrement. This organism is more resistant to disinfection than are many others, particularly when the disinfectant or chemical inhibitor is to be incorporated into a solid matrix, such as is the case with resinous materials. A bactericide with the ability to inactivate or destroy a Gram-negative bacterium like Escherichia coli has considerable technical and commercial advantage. It is also highly desirable that the bactericide be effective in relatively low quantities in order to avoid discoloration of material to which it is added such as resins.
Pseudomonas aeruginosa, another Gram-negative bacteria, is a health threat since it tends to spread infection and, in fact, is found in pus from body wounds. It is also found in polluted water and sewage and is a cause of human and animal lesions. Consequently, the ability to inactivate or destroy this organism is also important.
In addition, it must be borne in mind that the fact that certain compounds are effective against fungi would not for that reason suggest to one skilled in the art that the same compounds were also effective against bacteria. Likewise, the fact that certain compounds are effective against one classification of bacteria, such as Gram-positive bacteria, would not for that reason suggest to one skilled in the art that the same compounds would be effective against another classification of bacteria, such as Gram-negative bacteria.